Neptune's Dark Spots

Neptune is a stormy planet with the strongest winds in the Solar System. It also has areas of
highly intense storms. These are shown in the atmosphere by dark spots. The biggest dark spot, known as
the Great Dark Spot, was first observed in 1989 by Voyager 2 when it visited Neptune. This spot was
around the same size of Earth and is similar to the
Great Red Spot seen on Jupiter. The storms in the
spots also force icy methane crystals high up into the atmosphere of Neptune, forming white clouds.

The Hubble Space Telescope, a telescope orbiting
Earth to take pictures of
deep space, took pictures of Neptune but found that the Great Dark Spot discovered by
Voyager 2 had
disappeared, and that a new dark spot had appeared somewhere else (shown below). Nobody is sure why
this has happened, and why Neptune is able to lose its spots but
Jupiter still has one which has been
observed for hundreds of years.